Improved machine for separating- ores and other granular substances



" diritti Meer s. T. PEARCE, or New YORK, N. Y. Letters Patent No.87,361, dated March 2, 1869; antedated Februar/ry 18, 1869.

IllYi/IIEROVED MACHINE IIF'OIR SEPARATING- CRES AND OTHER GRANULARSUBSTANCES.

The Schedule xefen'd to in these Letters Patent and making parl: of thename.

To all 'whom it may concern:

Beit known that I, S. T. PEARCE, ofthe city, county, and State of NewYork, have invented a new and useful Improvement in Machinery forSeparating Ores and other Granular Substances; and I do herebydeclarethat the following is a full, clear, and exact description thereof,which will enable others skilled in the art to make and use the same,reference being had to the accompanying drawing, forming a part of thisspecification. f

This invention relates to improvements in machinery for sifting orscreening pulverized ores and other granular substances, for the purposeof sizing them.

It consists of an improved method of constructing rotating screens,whereby advantage is taken of centrifugal force to facilitate theoperation.

,It also consists of an improved order of arrangement of the screens,whereby the labor is materially lessened.

The drawing represents a sectional elevation of-one arrangement ofapparatus according to my invention.

A, B, and C, represent rotating sieves, arranged on the vertical shaftD, into which the material to be separated may be discharged, so as tofall at the central part, near the shaft. They are designed to be ofsuch a` degree of concavity, that the centrifugal action imparted to theparticles by the rotation ofthe sieves, will readily cause the finerparticles to pass through the meshes, while the coarser portion willvbeforced up over the top, into the outer receptacles E.

F represents the receptacles into which the finer portions fall afterpassing through the sieves, and from which they may be conveyed byspouts, as desired.

By this arrangement it is believed that a material economy will result,both in respect-of power and the amount of work accomplished,v as by theaction ofthe particles, under the effect of the centrifugal forceimparted to them, they will spread evenly over all the surface of thescreens, thereby bringing the whole `surface into constant and uniformaction; whereas, in

the action ofthe cylindrical, rotating, or dat reciprocating screens, asnow commonly used, only a part of the l `surface is in labor during thereciprocation or rtation, thereby necessitating the employment of a muchgreater area of surface and expenditure of power- It is often necessaryto separate ores into a great number of divisions or degrees ofiineness, and the common method is to pass the mass through an equalnumber of screens, varying in the degree of their reticulation,according to the required degree for the ores, each sieve separatingfrom the mass a succeeding finer or coarser degree of ore. I

To economize the labor of this processl I -propose to 'arrange thescreens in the order represented in the drawings, the operation of whichis as follows:

If it .be desired to separate a quantity of ore orother substance intofour grades, the sieve A, into which it is iirst discharged, should beof the proper size of reticulation to divide the mass into two equalparts, one of which, the ner, will be discharged into the sieve B, andthe coarser, into the sieve O, which are, in turn, of such a degree asto divide the part received by them into equal parts, thus resulting inthe four divisions required, as numbered in the drawing. These, again,may, in like manner, be passed into screens ofthe proper degree ofiineness to separate them equally, and so on to any extent.

The advantage of this arrangement is, that each screen, after the firstone, isburdened with a much smaller portion of the mass than is the caseaccording to the old method as above described; also, that the particlesacted upon by each screen are more nearly of 'f the size of the meshesof the screens, rendering the action of 'the same more natural anduniform.

' Having thus described my invention,

What I claim as new, and desire to secure by Letters Patent, is- I 1. Arotating sieve, arranged to impel the substance to be sifted, over itssurface, by centrifugal force, irnparted by' the rotation of the sieve,substantially as and for the purpose described.

2. The arrangement of a series of sieves, in the order herein described,substantially as and for the purpose set forth.

The above specification of my invention signed by me, this 28th day ofJuly, 1868.

Y S. T. PEAROE.

Witnesses .FRANK BLocKLEY, ALEX. F. RoBER'rs.

